Year	Years
1990	72
1991	72.2
1992	72.4
1993	72.6
1994	72.7
1995	72.8
1996	72.9
1997	72.9
1998	73
1999	73
2000	73.1
2001	73.2
2002	73.4
2003	73.6
2004	73.9
2005	74.2
2006	75.1
2007	76.1
2008	76.8
2009	77.3
2010	77.6
2011	77.9
2012	78
2013	78.1